I noticed quite a few people ask about sticking wider tyres on their bikes ... especially newbies, I hear things like
"my mate said he was gonna stick some wider tyres on the bike before he sold it to me because he said it will handle better"

Well, what absolute poppycock!!

Do not fit wider tyres to existing stock rims ... anyone who says do doesn't know what they're talking about ... they just want to sound like they do ..lol

It is just not a good idea, unless it is recommended by the motorcycle manufacturer, or you have changed the wheels.

If you put a wider tyre on the same rim often it deforms the natural profile of the tyre and can therefore cause adverse handling problems.

Road bikes are given the rim and tyre size to suit their on road handling and characteristics and usually most bikes far out handle their owners
with this in mind do you really think that "on the road" a wider tyre is really going to make you ride faster and handle better??

The best thing you can do is buy qualtiy OEM sized tyres and learn how to ride better :-)

Upgrade the rider first...




Jules

 

this wouldn't be rant would it??

I know what your saying, but IMHO, it all depends on the bike and the goals behind it wether or not to change tire size. Personally, I don't know enough to change the tire size, or have I ever come close to the limits of my bike.

In most cases, people just simply want to have a wider tire to look cooler. And in that case, I agree, its not worth it, and most likely, will upset the bikes handling.

However, some common swap wants are 180-190, and the rims for the 180 are usually a 5.5"-6" wide. which happens to the same recomendation for the 190. So in most cases, Not all, the same rim can be used as the both tires fit the same range of rims...... most of the time...

For the most part, a 190 will turn in slower than 180, but at the same time, can offer a better ballance and a more stabil ride through the corner once the bike has tipped in. Transitions will be slower as well. But, if you have a very twitchy bike, a 190 may be a solution. Also, many people go the oposite and run a 180 instead of a 190 for the opposite reason. A 180 will tip in quicker and transitions are faster. Wether or not the rider notices it on the street, who knows... but on a track, it could make a difference.

But, in near all cases, as you said, keeping with the stock size is the best course of action. Unless your running the bike on the track and want to experiement and have the money to burn. On the street, its not worth the chance of upsetting your bike with a tire that wasn't designed for the bike.

So in my opinion, not absolute poppycock..... but pretty darn close..

 

pfft!! ... I never rant, I just tell you how it is ... if you disagree I keel you!!

lol




I just found this article again buried deep down on my hard drive ... I knew I had something about it all somewhere :-)




Oversized Motorcycle Tires
By Jim Noss

What is the method behind the sizing of motorcycle tires? Why do certain motorcycles have certain tire sizes? Do the fatter tires you see on most bikes make the motorcycle handle better? How does one read the tire specification numbers on the tire sidewalls?

These are some of the basic questions I had when I first got into motorcycling. I will address each of these questions based on my research and personal experience.

There are numerous reasons why certain motorcycles have certain tires. As any sales person will tell you in their showroom, the intended use and desired performance of the motorcycle help determine the tire size. For example, most dual-purpose motorcycles like the BMW GS 1200 R and Kawasaki KLX 250 and KLR 650 will have tires suited for both off-road and street use. The KLX 250 tires will be more aggressive on the knobby side than the other dual-purpose motorcycles. Street bikes like the Kawasaki ZZR1200, will have a differently size tire than a touring and dual-purpose bike. Again, it all comes down to the intended use of the motorcycle.


When it comes to replacing the OEM stock tires, it is always wise to use a replacement tire with the same size as the stock tire for which you are replacing. The main reason for this is that the rims on your bike were designed to be outfitted with certain sized tires. Therefore, you need the correct size to fit on the stock rim.

Installing the correct size also implies that the tires have the same circumference. Having two different tire circumferences will have negative effects on your motorcycle’s tire grip and overall handling. Why is this so? A motorcycle’s rake and trail and the front and rear weight bias are affected by the ride height of the front and rear ride height. This is why tire circumference is important.

Recently with motorcycles like the Victory Hammer, you see more fat and wider tires being installed on motorcycles for both performance and style. Be sure the stock rim is designed to handle these wider tires. If you are installing a wider tire on a narrower rim for which it was not designed to handle, the footprint of the tire diminishes due to the profile being wrong. Another thing to be cautious of is that a wider tire may not have enough clearance once installed and rub against the fender or swing arm.

The bottom line is that the sizing of tires for certain motorcycles is determined by the factory motorcycle and tire engineers. They know their science well and know what works best on certain motorcycles. They have devised a numbering system which is used when replacing your tire. It is not a user-friendly numbering system but it makes sense to the tire manufacturers. For example a 100/80-18 tire means the 100 is the nominal width in millimeters. The 80 is the aspect ratio, and refers to the height of the tire as a percentage of the width (in this case 80 percent of 100mm). The 18 is the wheel’s diameter in inches for which the tire is designed to fit. So replace your tires based on what your manual says. Why risk putting on a different size tire just for looks at the risk of safety and performance.

 

Except in racing its all for bling and hurts the bike handling!